Notes

In cattle, a dramatic increase in plasma estradiol occurs during the short 2- to 3-day follicular phase
The objective of this study was to investigate the molecular mechanisms that mediate this critical change, specifically whether increases in the steroidogenic ability of granulosa and thecal cells of the preovulatory follicle are associated with increases in the levels of messenger RNA (mRNA) for steroidogenic enzymes. Luteolysis and a follicular phase were induced cycling Holstein heifers (n=15) by injection of a luteolytic dose of prostaglandin F2 alpha (PGF 2 alpha) on day 6 or 7 of the estrous cycle (day 0 = estrus), and preovulatory follicles were obtained at three stages of differentiation (0, 12, or 24 h post-PGF2 alpha treatment). To assess developmental changes in steroidogenesis in vivo, estradiol and androstenedione were measured in follicular fluid and in culture medium after a 3-h incubation of granulosa and thecal cells in defined medium with or without gonadotropins. To determine whether changes in mRNA for steroidogenic enzymes are associated with changes in follicular steroidogenesis, levels of mRNA for cytochrome P450 side-chain cleavage (P450scc), 3 beta-hydroxysteroid dehydrogenase (3 beta HSD), cytochrome P450 17 alpha-hydroxylase, and cytochrome P450 aromatase (P450arom) were measured in thecal and granulosa cells using ribonuclease protection assays. Concentrations of estradiol in follicular fluid were relatively high at time zero, increased significantly by 12 h, and increased further by 24 h post-PGF2 alpha treatment. However, the aromatizing activity of granulosa cells was high at the time of PGF2 alpha injection and did not increase significantly during the first 24 h after the initiation of luteolysis.

The aromatizing activity of granulosa cells was reflected in levels of mRNA for P450arom, which was relatively abundant in granulosa cells obtained before luteolysis and did not increase further during the first 24 h of the follicular phase. Concentrations of androstenedione were virtually undetectable in follicular fluid at time zero and had increased dramatically by 12 and 24 h post-PGF2 alpha treatment. Similarly, thecal cells isolated at 24 h secreted 3-fold more androstenedione than cells isolated at the time of PGF2 alpha injection. Androstenedione production by thecal cells in response to LH was also markedly higher at 12 and 24 h than at the time of PGF2 alpha injection. Likewise; levels of mRNA for P450 17 alpha-hydroxylase increased significantly by 12 h post-PGF2 alpha treatment.(ABSTRACT TRUNCATED AT Seebio Photobase Generator )An ionic aromatization of steroidal dienones.Differential cytotoxicity to human cells in vitro of tire wear particles emitted from typical road friction patterns: The dominant role of environmental Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Nanjing University of Information Science and Technology, Nanjing, 210044, Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Nanjing University of Information Science and Technology, Nanjing, 210044, Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Nanjing University of Information Science and Technology, Nanjing, 210044, Tire wear particles (TWPs) have been recognized as one of the major sources of microplastics (MPs), however, effects of initial properties and photochemical behavior of TWPs on cytotoxicity to human cells in vitro have not been reported.

Therefore, here, three TWPs generated from typical wear of tires and pavements (i.e., rolling friction (R-TWPs) and sliding friction (S-TWPs)) and cryogenically milled tire tread (C-TWPs), respectively, and their photoaging counterparts were used to study the reasons for their differential cytotoxicity to 16HBE cells in vitro. Results showed in addition to changes of surface structure and morphology, different preparation methods could also induce formation of different concentration levels of environmental persistent free radicals (EPFRs) (from 14 to 36 × 1017 spins/g with g-factors ranging 20307-20310) on surfaces of TWPs, which contained 7%-65% of reactive EPFRs (r-EPFRs). Meanwhile, photoaging for 90 d could strengthen formation of EPFRs (from 43 to 41 × 1017 spins/g) with containing 74%-78% r-EPFRs on surfaces of TWPs and improve their g-factor indexes (ranging 20309-20313). At 100 μg mL-1 level, compared to C-TWPs, both R-TWPs and S-TWPs (whether photoaging or not) carried higher intensity EPFRs could significantly inhibit 16HBE cells proliferation activity, cause more cells oxidative stress and induce more cell apoptosis/necrosis and secretion of inflammatory factor (P < 05). However, regardless of how TWPs were prepared, photoaged or not, exposure at a concentration of 1 μg mL-1 appeared to be non-acute cytotoxic.

Correlation analysis suggested dominant toxicity of TWPs was attributed to the formation of r-EPFRs on their surfaces, which could promote accumulation of excess reactive oxygen species in cells and the massive deposition of intracellular particles.
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